Lens settings missing from camera settings
This was a bug in an early pre-release version of Blender 2.80 which was fixed in February 2019.

https://developer.blender.org/T61499
https://developer.blender.org/rB5e3838faa2e6dae0ac52860085f5dc4b7a000ea5

You should at least update to the proper release of Blender 2.80 or, if your hardware supports it, the current long-term support (LTS) version Blender 2.83.6 or the most recent release Blender 2.90.
The LTS is a version of Blender that will continue to receive bug fixes for a span of 2 years after its initial release, while the 2.90 release will be superseded by 2.91 in November 2020.

The Blender LTS program is aimed at ensuring that long-lasting
projects can be executed using a stable Blender version, which will
provide critical fixes throughout a 2-year time span. The LTS version
will not have any new features, API changes or improvements. Any
critical fix that is applied to the 2.9 series will be regularly
ported over to Blender 2.83 LTS.